Microsoft Looks Into Zero-Day Windows Browser Vulnerability

Microsoft has been alerted to a Windows vulnerability that could be used to perform remote code execution. The researcher, only identified by the "Cupidon-3005" moniker, also posted the proof-of-concept exploit code that triggers a blue-screen PC lock-up.

All versions of Windows are affected by the vulnerability, and Microsoft cautions that primary domain controllers are at the highest risk of being attacked.

In a TechNet blog, Matt Oh, member of the MMPC Vulnerability Response Team, provided some more details on the situation: "...the vulnerability is inside an error-reporting function of the CIFS browser service module. The function gets a variable number of arguments as parameters. Those string arguments are pushed on the stack for processing. In some cases, some of the strings can be controlled by the attacker."

Oh continued by saying that once a PC is controlled by a hacker it could be possible for malicious code to be freely distributed to the compromised system.

The Microsoft security team is very optimistic that exploitations of the vulnerability for this purpose should be rare. The team added that "while [a remote code execution] is theoretically possible, we feel it is not likely in practice, wrote Mark Wodrich, MSRC engineer, in a blog post.

However, Wodrich does feel that there is some concern that hackers may use this newly documented opening to launch a denial-of-service attack.

Microsoft has not yet released a security advisory on the vulnerability and has offered no workaround fix as it continues to investigate the security concern. With the release of February's patches just last week, an official patch may not surface until Microsoft's March security update, or Microsoft could release an interim "out-of-band" patch.